Well, yokozuna is the very highest rank in sumo. If you're a yokozuna, you're a top champion. Sometimes there are no yokozuna, and at other times there have been three or four at the same time. The name comes from the rope – called a tsuna – that the yokozuna wears. The rope can weigh up to 20 kilos but it's not used during matches. It's only worn before matches, during a special ceremony.